Microwaves are at the lower energy end of the electronic radiation spectrum which includes gamma rays, X-rays, ultraviolet, visible light, near infrared, infrared radiation, microwaves and radio waves. Microwave processing offers advantages over conventional oven heating for some food products because it produces rapid product heating without excessively high surface temperatures. However, this type of heating is "opposite to" conventional cooking of foods with respect to moisture and heat transfer.
Convenience is a major factor in the popularity of microwave ovens. Consumer surveys have shown that microwave market penetration has reached 70% of the households with projections for growth extending through the 1990's. Along with the increase in penetration of the microwave oven into the home has come a demand for microwaveable food products.
There has been a large expansion in the number of microwave foods available on the market. However, typically this has amounted to the inclusion of microwave directions and not food reformulations for textural attributes. Particularly in the area of bread-like foods, little, if any, improvement in textural attributes has been made in commercially available products. It has thus not been desirable to reheat or cook such products in a microwave oven. Pre-cooked and uncooked products may exhibit excessive toughness and firmness from exposure to microwave radiation.
The present invention relates to solutions for overcoming or reducing at least two problems relating to crumb texture attendant with heating pre-cooked or uncooked bread-like products in a microwave oven. Pre-cooked and uncooked bread-like products may exhibit both toughness and firmness as a result of microwave heating.
A major technical difficulty for microwaving bread-like products is the development of the above discussed unacceptable texture. The outer, crust layer may become so tough that it is difficult to tear such a product. The inner crumb may become very difficult to chew. Also, the textural quality can deteriorate much faster than that of a conventional oven baked product during the course of cooling. Overcooking in a microwave oven may exacerbate the problem while a reduction in overall cooking or reheating may reduce toughness and/or firmness.
It has been reported that Oscar Mayer & Co. developed a microwaveable sandwich by using a specific type of starch, and a precise ratio of starch to fat to flour in the dough (Anonymous, 1987). One method of dealing with texture problems is to use a specially designed protein system in the dough which has been reported not to become tough during microwave treatment (Moore, 1979). Another approach, as disclosed in U.S. Pat. No. 4,463,020, requires the use of long grain rice flour in the dough. An approach described in U.S. Pat. No. 4,560,559 requires the addition of starch granules having an average size of less than approximately 20 microns. It has been reported that fat in combination with other substances reduced toughness in microwaveable dough-based items (Kimbrell, 1987). The tenderizing effect of fat has been attributed to the "shortening effect". U.S. Pat. No. 4,015,085 for a container for the microwave heating of frozen sandwiches to F. J. Woods discloses a sandwich which is reheatable in a plastic pouch. It uses a metal shield adjacent to one surface of the sandwich. Controlled heating is accomplished by controlling the aperture size and number in the shield. There is a discussion about such products becoming unpalatable, for example, becoming rubbery to the feel and taste when heated. A moisture absorbent layer is also provided. It is disclosed that the package allows for the increase in temperature of the product from a frozen or refrigerated condition without harming the palatability of any portion of the product.
Formulas suitable for dough-based and batter-based products and other processing criteria are set forth in patent applications entitled "Starch-Based Products for Microwave Cooking or Heating" by Victor T. Huang et al. and "Dough Based Products for Microwaving" by Jean L. Weber et al. the entire disclosures of which are incorporated herein by reference. These applications were filed contemporaneously herewith.
Toughness can be defined and assessed in sensory terms as a leathery or rubbery eating texture. For example, a bagel is tough while a croissant is tender. Firmness can be defined and assessed in sensory terms as the force required to bite through the sample without tearing or pulling. A "stale" dough-based product can be characterized as firm while fresh bread immediately after conventional cooking would be considered non-firm.
Whether or not a product is tough or firm or, more accurately, is objectionably tough or firm, depends on the product type and the consumer. For example, the expectation for bread is that it should be soft and not tough. If bread had a bagel texture it would be objectionable because of the toughness. However, a bagel, even though it is tough, is not objectionable since the expectation is for a product that has a tough texture. Thus, the type of product and the consumer will set the standard for what level of toughness or firmness is objectionable, desirable.
One of the complicating factors in dealing with bread-like systems is that minor changes in the formula or process can change the product identity from one product to another product. For example, further development of a biscuit dough will produce a baked product which is more of a bread, and frying of a yeast leavened product will produce a doughnut while baking of the same yeast leavened dough will produce a bread-like product. Thus, a careful balance must be made in the Processing and the formula to solve product problems and not change the product identity.
Three criteria are the major determining factors for product identity. Those criteria are: the flour type and its protein content; the amount of fat; and the degree of dough development. See FIG. 1 for examples.
Additional factors may affect product identity. Some of these factors include, for example: type of fat; type of leavener; dough formation method; method of fat inclusion; method of cooking the product e.g., steaming, frying, baking, etc.; method of assembling the dough product, for example, laminating versus nonlaminating, etc. These and other related factors and principles are discussed in Hoseney (1986). Further, the same cereal grain can provide major differences in the product. For example, changing from a soft wheat to a hard wheat can significantly change the product identity. Dough-based and batter-based products may be prepared from one cereal grain flour or mixtures of several cereal grain flours. For dough-based products, the cereal flour should be capable of forming a viscoelastic continuous protein matrix upon hydration.
With the present invention, toughness and firmness can be reduced from any point along scales that range from non-tough and non-firm products to very firm and tough products. More specifically the present invention involves methods to reduce toughness and firmness and provides the latitude to reduce toughness and firmness regardless of the original toughness and firmness for a similar non-invention product.
The present invention involves means and method to reduce the degree of the above-mentioned toughening and/or firming of bread-like products upon their heating e.g. reheating or cooking by microwave irradiation.
Embodiments of the invention can provide improved quality in microwaveable bread-like products including unleavened and leavened products. Leavened products include those leavened by microorganisms such as yeast, chemicals, steam, etc. as is known in the art. By use of the present invention, therefore, an improved quality microwaveable product including reconstitutable dry mix, fresh or raw dough, frozen dough or pre-cooked bakery products may be prepared in the microwave oven.
The present invention can be practiced with starch containing or starch based product. These products can take the form of dough products and non-dough products. Dough products will exhibit toughness and often firmness as a textural problem. Dough-based can be defined as a product which has a continuous matrix of gluten. Preferably such products have at least 4% gluten by weight in the dry flour. More preferably a dough-based product will have 6% or more gluten by weight of dry flour. Non-dough products, hereinafter referred to as batter-based products, are characterized in that they have minimal or no gluten matrix in the plasticized mixture of flour and plasticizers. Generally, batter-based products have low gluten i.e., less than about 8% gluten by weight of dry flour, and can have no gluten. Batter-based may exhibit firmness as a result of microwave heating and not toughness because of the lack or low degree of continuous gluten matrix.
As hereinafter discussed, toughening is predominantly a protein related phenomenon, more specifically a gluten related phenomenon. Also as hereinafter discussed, firming is a predominantly starch related phenomenon. For the practice of the present invention any cereal grain based product from which a dough or batter can be made, can be utilized. Firming in these products may be improved by practice of this invention. Products containing on a dry flour basis, at least 4% gluten may utilize the invention to reduce toughening. Combinations of cereal grains can also be utilized to form a dough or batter. Cereal grains include wheat, corn, rye, barley, oats, sorghum, triticale, etc.
As used herein, the phrase bread-like product is not limited to breads as defined in the standards of identity under the Food, Drug and Cosmetic Act. Bread-like or bread-type products include such foods as breads, biscuits, cornbread, quickbreads, pastries, sweet rolls, pita bread, pie crust, pasta, dumplings, pizza crust etc. whether or not the product is made from a dough-based product or batter-based product as defined herein.
As used herein, the term "dough-based product" includes products that are partially cooked or cooked and were in a dough form just prior to cooking by any means. The term "dough-based product" also includes products that are dough prior to cooking or reheating in a microwave oven. Dough may be defined as a viscoelastic substance which is developed or partially developed.
As used herein, the term "batter-based product" includes products that are partially cooked or cooked and were in batter form just prior to cooking. The term batter based product also includes products that are batter prior to cooking or reheating in a microwave oven. Batter may be a liquid or can be a pasty material much like "brownie dough" or "cookie dough".
A product intermediate is either a dough based or batter based product in whatever form, for example, in a cooked, partially cooked or uncooked (raw) state just prior to exposure to microwave radiation.
An acceptable texture is more like the texture of a conventionally cooked equivalent or similar product as is known in the industry. Conventional cooking includes convection, conduction, non microwave irradiation like radiant heat cooking, electrical resistance heating i.e., the food product or bread-like product is used to conduct current, etc. The invention product texture is better than the texture of an equivalent product without using the invention. For purposes of this disclosure, a similar or equivalent product is a product that has substantially the same formula and is also analogously processed i.e., it is processed in the same way and pre-cooked and/or heated the same, except for use of the invention. It is preferred that the improvement in product with the invention relative to a similar product without the invention is distinguishable to a consumer and is at least about 5 and preferably at least about 10 points on a 0-60 organoleptic relative sensory testing scale (with 60 representing high toughness or firmness) using a trained panel. Such a testing procedure is known in the art. It is preferred that the improvement in the product with the invention relative to a similar or equivalent product without the invention is at least about 10% and preferably at least about 20% or more improvement on the relative sensory testing scale as described herein.
The products of the present invention comprise flour and sufficient plasticizer to form a dough or batter. The dough or batter can include aqueous and nonaqueous plasticizers. Nonaqueous plasticizers include fats however in some products added fat is not necessary for example French bread. The water content used herein, unless otherwise indicated, is added water. It is to be understood that flour contains approximately 14% water by weight of flour.
In accordance with an aspect of the present invention, an improved quality cooked or uncooked microwaveable product can be produced, such products can be distributed, and/or stored under conditions such as frozen, refrigerated (pressurized or unpressurized), and shelf-stable systems.
An advantage of the present invention is that the treatment means for the dough-based or batter-based products is effective in reducing microwave induced toughness and firmness a distinguishable amount.
Another advantage of the present invention is that the treatment means for reducing toughness and/or firmness does not require special processing equipment to effectuate.
Another advantage of the present invention is that the treatment means is effective for reducing the toughness or firmness from any level of toughness or firmness for an equivalent product that does not utilize the treatment means.
Other objects will become apparent from a review of the specification.